Search results for "Mathematica"
showing 10 items of 7971 documents
Different energy balances for the redesign of nearly net zero energy buildings: An Italian case study
2015
Abstract The currently developing concept of a Net Zero Energy Building introduces new challenges and research problems. The calculation of a net zero energy balance is heavily influenced by the energy carrier weighting factors that are chosen, which can deeply influence the future energy market towards adopting specific energy technologies. The following paper proposes an analysis of different definitions and conventions for Net Zero Energy Buildings that employ different calculation methodologies and apply different weighting factors to an Italian case study. The case study, which is called “the Leaf House”, is one of the first examples of a nearly net zero energy building in Italy. A bui…
Mixed heuristic-non linear optimization of energy management for hydrogen storage-based multi carrier hubs
2014
In this paper, an heuristic and non-linear programming based algorithm to optimally operate an energy hub plant is proposed. The energy hub plant described in this work is the test system for the European INGRID research project. The Energy Management System defines the optimal energy flows dispatch in order to obtain the energy balance and the maximum profit for the owner of the plant. The problem is highly constrained and non-linear, for this reason the methodology cannot rely on Linear Programming (LP) methods. The Energy Management System manages two energy carriers, electricity and hydrogen, interfacing three distribution networks: the electricity, the hydrogen and the methane networks…
Unit Vector Fields that are Critical Points of the Volume and of the Energy: Characterization and Examples
2007
In the last few years, many works have appeared containing examples and general results on harmonicity and minimality of vector fields in different geometrical situations. This survey will be devoted to describe many of the known examples, as well as the general results from where they are obtained.
ROUGHNESS CONTROL OF PARTS OBTAINED THROUGH INCREMENTAL SHEET FORMING
2007
Abstract The present paper adresses the issue of controlling the quality of surface in the case of a new sheet metal forming process by which various curved shells are formed without the help of expensive dies. The roughness of the surface which comes in direct contact with the punch at incremental sheet forming suffers an obvious worsening compared to the initial blank surface roughness. The present paper discusses the measuring of the roughness of parts obtained through the previously mentioned process and highlights the factors that influence it. There were taken into account the initial roughness of the punch, the punch diameter and the friction coefficient between the punch and the bla…
Residual Stresses due to High Temperature Annealing. Mathematical Model and Calculations
2006
The mathematical model is developed for description of thermomechanical processes at cooling during high temperature annealing with the known initial temperature distribution (the temperature of holding) and stresses (acquired stresses at the final of a holding). It is taken into account the thermal sensitivity and material hardening at elasto-plastic solid deforming. The methodology based on the finite element method is proposed for solving thermomechanics problems of wide range. The suitable software is developed. At the final stage of annealing a cylindrical solid it is investigated residual stresses being formed on the cooling stage.
Advanced models for smart multilayered plates based on Reissner Mixed Variational Theorem
2017
In the present work, families of equivalent singe layer and layer-wise models for the static and free vibrations analysis of magneto-electro-elastic multilayered plates are developed. The models are defined in the framework of a unified formulation, which offers a systematic approach for generating refined plate theories through suitable expansions of the through-the-thickness components of the relevant fields, considering the expansion order as a free parameter. The key features of the developed formulation are: a) the condensation of the electric and magnetic description into the mechanical representation, based on the quasi-static electric-magnetic approximation, which allows to reduce t…
Vegetation and soil – related parameters for computing solar radiation exchanges within green roofs: Are the available values adequate for an easy mo…
2016
Several studies analyze the thermal performance of vegetated roofs, presenting either mathematical models or experimental quantifications of heat transfer process through them, also showing the effect of vegetation and soil parameters on the thermal and energy performance of this type of roofing system. However, presently the level of availability of these parameters, has not been enough considered. This work intends to investigate this underestimated issue of the green roofs’ thermal modeling, through the consideration of the availability of parameters pertinent to the shortwave radiation exchange, which are adopted by models based on leaf area index (LAI) and on the fractional vegetation …
A multilayer anisotropic plate model with warping functions for the study of vibrations reformulated from Woodcock's work
2013
Abstract In this paper, a suitable model for static and dynamic analysis of inhomogeneous anisotropic multilayered plates is described. This model takes into account the variations of the transverse shear strains through the thickness of the plate by means of warping functions. Warping functions are determined by enforcing kinematic and static assumptions at the interfaces. This model leads to: a 10×10 stiffness matrix coupling to each other the membrane strains, the bending and torsion curvatures, and the x and y-derivatives of the transverse shear strains; and a classical 2×2 transverse shear stiffness matrix. This model has been proven to be very efficient, especially when high ratios be…
S-domain modeling of conducting post in rectangular waveguides by the BI-RME method
2002
This paper describes the application of the Boundary Integral - Resonant Mode Expansion method to the modeling of a conducting post in a rectangular waveguide. The mathematical model of this structure is determined in a very short time, in the form of pole expansion of the Generalized Admittance Matrix in the s-domain. This model is very useful in the CAD of combline or interdigital filters.
A Novel Wideband MIMO Car-to-Car Channel Model Based on a Geometrical Semi-Circular Tunnel Scattering Model
2016
In this paper, we present a wideband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on a geometrical semi-circular tunnel (SCT) scattering model. From the geometrical SCT scattering model, a reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. In the proposed reference channel model, it is assumed that an infinite number of scatterers are randomly distributed on the tunnel wall. Starting from the geometrical scattering model, the time-variant transfer function (TVTF) is derived, and its correlation properties in time, frequency, and space are studied. Expressions ar…